Did a nice winter start and fought my way through with ample food and meds. Ambient temperature was around 14C but I always made a point to keep the base at 15C at least. Came back from my nightly plundering and Katia froze to death... from perfect health in sunny weather.
I'm not sure what caused it but I did have two heaters one of which was empty. The other had 3 fuel in it keeping the base after death at 18C. The Bio text complained that they needed to add fuel to the heater to keep warm. Perhaps she decided all the left over snow from winter would make a comfy chair for guard duty?